Chain saw adjuster mechanism with locking teeth

Abstract

A tensioning mechanism for adjusting tension of a cutting chain in a chain saw. A rotatable knob operates with an engine chassis, clutch cover, and guide bar, whereby the knob may be rotated between a tightened position and loosened position, by which the guide bar is loosened and may be adjusted. The knob is provided with a knob handle, pivotally connected to the knob and pivotable between locked and unlocked positions. When the knob handle is in the locked position, at least one, but not all, of a plurality of handle engagement points engage with corresponding fixed engagement points that are fixed relative to the clutch cover. When the knob handle is in the unlocked position, the handle engagement points are disengaged from the fixed engagement points. Further, the engagement points are visible when the knob handle is in both locked and unlocked positions.

1. A tensioning mechanism for adjusting tension of a saw chain in a chain saw having an engine chassis, a clutch cover, and a guide bar, the mechanism comprising:
 a rotatable knob operatively cooperative with the engine chassis, the clutch cover, and the guide bar, wherein the knob can be rotated between a tightened position, in which the guide bar is tightened between the engine chassis and the clutch cover, and a loosened position, in which the guide bar is loosened and may be adjusted;  
 a knob handle, having an end portion pivotally connected to the knob, and a lock portion extending from the end portion, wherein the knob handle is pivotable between a locked position and an unlocked position;  
 a plurality of fixed engagement points fixed relative to the clutch cover; and  
 a plurality of handle engagement points extending from the lock portion of the knob handle, wherein  
 at least one of the handle engagement points engages with respective fixed engagement points when the knob handle is in the locked position, and the handle engagement points are disengaged from the fixed engagement points when the knob handle is in the unlocked position, and  
 the handle engagement points and the fixed engagement points are visible when the knob handle is in the locked position and when the knob handle is in the unlocked position.  
 
   
   
     2. A tensioning mechanism as set forth in  claim 1 , wherein the handle engagement points extend radially with respect to a rotational axis of the knob. 
   
   
     3. A tensioning mechanism as set forth in  claim 1 , wherein the handle engagement points are at a radially outer periphery of the knob handle with respect to a rotational axis of the knob. 
   
   
     4. A tensioning mechanism as set forth in  claim 1 , wherein at least one of the handle engagement points engages with respective fixed engagement points and the remaining handle engagement points are not engaged with the fixed engagement points when the knob handle is in the locked position. 
   
   
     5. A tensioning mechanism for adjusting tension of a saw chain in a chain saw having an engine chassis, a clutch cover, and a guide bar, the mechanism comprising:
 a rotatable knob operatively cooperative with the engine chassis, the clutch cover, and the guide bar, wherein the knob can be rotated between a tightened position, in which the guide bar is tightened between the engine chassis and the clutch cover, and a loosened position, in which the guide bar is loosened and may be adjusted;  
 a knob handle, having an end portion pivotally connected to the knob, and a lock portion extending from the end portion, wherein the knob handle is pivotable between a locked position and an unlocked position;  
 a plurality of fixed engagement points fixed relative to the clutch cover; and  
 a plurality of handle engagement points extending from the lock portion of the knob handle, wherein  
 at least one of the handle engagement points engages with respective fixed engagement points and the remaining handle engagement points are not engaged with the fixed engagement points when the knob handle is in the locked position, and  
 the handle engagement points are disengaged from the fixed engagement points when the knob handle is in the unlocked position.  
 
   
   
     6. A tensioning mechanism as set forth in  claim 5 , wherein the handle engagement points and the fixed engagement points are visible when the knob handle is in the locked position and when the knob handle is in the unlocked position.